A blaze at the company was reported before dawn, and while firefighters were trying to douse the flames, the fire spread to a truck with a gas tank, which then exploded.
Sicius said one of the injured firefighters was in critical condition, but his injuries weren't believed to be life-threatening. Most of the other firefighters were treated at surrounding hospitals for burns and smoke inhalation.
Residents were taken to nearby Dudenhofen and put up at a gymnasium, while police were patrolling the abandoned village to prevent burglaries.
The explosion was so strong that it could be heard in Ludwigsburg, which is 30 kilometers (about 20 miles) away. Two other gas tanks were catapulted onto a nearby field and an empty storage building by the blast wave. For fear of further explosions, residents won't be allowed to return home until at least Sunday, police said.
The cause of the fire wasn't immediately known, but German news agency dpa reported that investigators were looking at arson as one possible reason for the fire.